Vacuum plate



H. w. KLEIST VACUUM PLATE Filed March 18, 1946 [ravenfor 'fermarz WIZeZQSzf vl fi=; Te

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Patented Feb. 24, 1948 VACUUM PLATE Herman W. Kleist, Chicago, Ill., assignor to Dole Refrigerating Company, Chicago, 11]., a corporation of Illinois Application March 18, 1946, Serial No. 655,338

Claims. 1

My invention relates to an improvement in cold plates, and has for one purpose to provide an improved plate in which a pressure differential is employed to hold the sides of the plate inwardly against a coil or spacer system within the plate.

Another purpose is to provide a plate of the above type, in which rectangular coil lengths are employed.

Another purpose is to provide a plate of the above type, in which the coil lengths are arranged in parallel within the plate.

Another purpose is to provide a plate of the above type, in which headers are enclosed within the plate.

Another purpose is to provide a plate in which the headers, within the plate, are rectangular in cross section.

Another purpose is to provide a plate in which the coil lengths and headers are of the same thickness.

Another purpose is to provide a plate in which the headers and coil lengths have opposite parallel faces lying in a common plane.

Other purposes will appear from time to time throughout the specification and claims.

I illustrate the invention more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a plan view with parts broken away and parts in section;

Figure 2 is a section on an enlarged scale taken along the line 22 of Figure 1;

' away. illustrating another variant form; and

Figure 7 is a section along the line 1-1 of Figure 6.

Like parts are illustrated by like numbers throughout the specification and drawings.

Referring to the form of Figures 1 to 4. inclusive, I illustrate a plate structur which includes an outer housing formed by opposite and parallel sheet metal plates I and 2. They are sealed together at their edges to form a liquid and gas tight container. I illustrate for example a circumferential flange 3 formed on the plate 2 and sealed or otherwise secured, as at 4, to the plate I, the plate I having an outwardly extending circumferential edged portion 5. 6 is a header, shown as having walls defining a rectangular space which is broader, in the plane of the plate, than in a plane perpendicular to the plate It may conform fairly closely to the opposed portions of the sheets or plates I and 2 and the flange 3, as shown in Figure 2. At the opposite end of the plate is a second header 1, which may be identical in structure with the header 6. Each header has a closed end wall, 8 and 9 respectively. Each header is provided with an outside section through a coupling III or II secured to any suitable duct I2 or I3. Thus a refrigerant can be delivered to the header 8 from the duct I2, and can be withdrawn from the header I through the duct I3, or the direction of circulation can be reversed.

The headers are connected by a series of evaporator ducts or tubes I4. They are all shown as square, but can, if desired, be made of any suitable, but preferably rectangular, cross section. The members I4 are received through apertures I5 in the headers. These apertures may be rectangular and may simply be milled out portions of the opposite inner side poles of the two head-- ers. The tubes I4 are shown as extending slightly into the interiors of the headers, as will be clear at Na in Figure 1. The tubes are then welded or otherwise secured as at I6 to the headers, to provide a gas tight evaporator system. For convenience, I may described the headers and connecting tubes as an evaporating coil.

It will be observed as in Figure 2 that the tubes I4 have parallel upper and lower walls I41: and I40. The opposite outer faces of these walls are adapted to engage and conform to the inner faces of the members I and 2 respectively, The corresponding walls 6b and 6c of the header 6 have their outer faces lying in the same planes as the outer faces of the walls I41) and I40. The header I is similarly formed. Thus in the completed vacuum plate I have a structure in which a plurality of parallel evaporator tubes I4 are connected at each end to headers 6 and I, the system thus formed having opposite and parallel faces adapted to conform closely, through their area, to the inner faces of the members I and 2. In order to maintain a close contact between the coil system and the plate walls, I prefer partially to exhaust the interior of the plate. In order to do so I provide a fitting 20 put into communication with the interior of the plate by a passage 2|. The fitting 20 is provided with a screw-threaded bore 22 adapted to be closed by the screw-threaded plug 23. The ball 24 serves to close the passage 2|. Any additional sealing means may be employed, in the space about the ball, or between the members 22 and 28. when the interior of the plate is partly exhausted, by any suitable compressor, the diflerence in pressure will, normally hold the ball 24 in the sealing position in which it is shown in Figure 4. Thereafter the additional sealing material may be inserted about the ball, or about the plug 28, then plug 28 is screwed into the closed position in which it is shown in Figure 4.

I find it advantageous, under many circumstances, partially to fill the space within the plate, outside of the coil system, with suitable eutectic. When I do so I find it advantageous to refrain from sealing the interior of the plate completely. If a void of the order of ten per cent or somewhat less is left, space is provided to permit the eutectic to expand when frozen without substantially expanding or rupturing the plate.

In the form of Figure I illustrate a structure which is substantially the same as that shown in Figure 1 except that I employ headers oi somewhat greater thickness than the coil or evaporator tubes. Thus the tubes ll, which may be square in cross section, as shown in Figure l, in apertures ll in the side wall of a header 3! which is of perceptibly greater thickness than the tubes 30. In that event the opposite plate walls a and 14 are termed snugly to engage the walls 30a and 30b of the ducts 30. They are outwardly offset as at I5 and 36 and terminate in parallel portions 31 and 38 which snugly engage the opposite walls 32a and 32b of the header 32. The two plate walls can be joined in any suitable manner. However, I illustrate them as turned about and engagingthe outer wall 32c oi the distributor and as being Joined together and welded or otherwise secured together in sealed relationship as at 3!. In the plate structure as thus formed, the body of the plate has opposite plane, parallel faces, put along opposite edges orgends of the plate. The plate structure is enlarged to accommodate the'two headers. Any suitable duct connections, not herein shown, but like the connections i2 and ll of Figure 1, may be employed for the opposite header of the plate of Figure 5.

With reference to Figure 6, I illustrate another variant form in which I employ generally cylindrical headers 40 connected by preferably rectangular tubes ll. The diameter of the headers 40 is greater than the corresponding diameter of the rectangular tubes ll. Any suitable outer plate wall structure 42 surrounds the system thus formed. It will be understood that any suitable outlet or inlet means may be employed for the two headers, and any suitable means such as those shown in Figure 4 may be employed for partly exhausting the interior of the plates of Figures 5 and 6.

It will be realized that, whereas, I have described and illustrated a practical and operative device, nevertheless many changes may be made in the size, shape, number and disposition of the parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustra-v tive or diagrammatic, rather than as limiting me to my precise showing.

are connected at their ends by headers l and 1.

When-a volatile refrigerant is supplied to one the entire battery of tubes II, the evaporated or partly evaporated refrigerant is withdrawn from the opposite header. The combined tube structure forms a positioning re-enforcement for the outer walls I and I, and the result is a plate structure of maximum rigidity and strength. The use of an eutectic in the interior of the plate, in the space surrounding the tube or coil structure, permits the formation of a film between the opposed faces of the tube or coil structure and the walls of the plate. A very advantageous heat transfer condition is thereby maintained. If the invention is employed for a connection plate, a flow portion of a suitable liquid. having vapor pressure, is employed, to maintain the desired film. In either event, a sufiicient pressure diflerential is established in order to cause the outside atmosphere to thrust the walls I and 2 firmly against the opposite walls of the tube system. The parts are so proportioned that there will be a maximum area of contact and a strictly uniform clearance, the opposed surfaces having 'a film between them which has the eiIect of maintaining highly efiicient heat exchange conditions. In the form of Figures 1 to 4, the plate has opposite faces which are parallel from edge to edge. In the form of Figures 5 and 6, the plate has enlarged portions along opposite sides or edges. This maybe advantageous, where a plate of considerable length is used, and the enlarged portions are preferably along parallel long sides of the plate. The enlarged edge portion serves as a space of truss and stabilizer re-enforcement. Where the plate is used in connection with a conveyer, as where material is scrapped or pushed along the plate, the enlarged side portions may be advantageous as limiting means for the material treated.

I find advantageous to have the headers or manifolds extending snugly along opposite sides or edges of the plate. This results in a very even cooling eiIect with a uniform temperature along the edges of the plate.

Another advantage is in ease and economy of assembling. Square or rectangular tubes, for both evaporating ducts and headers, may be bought in large lengths. They can then be cut to proper lengths and the apertures along the sides of the headers may be milled out to just the right size to receive the tube ends. No bending of any tubes is necessary. The tubes may even be delivered. cut to size, at the plant where the plates are to be assembled. In assembling the plates, the tube and header structure is first assembled and completed. the tubes being inserted in the header apertures, and welded. The evaporator structure may then be checked for irregularities in dimension and milled or ground down to uniform thickness. The plate wall sheets I and 2, formed with the circumferential flanges 3 are then assembled about the evaporator structure and welded in proper position. The proper outside fittings or connections such as it and ii are then welded in place, and the plate is ready for its charge oi eutectic. Thereafter it is exhausted and sealed as above described.

' header, the reirigerant flows in parallel thrwsh evaporator structure. However. it is important that the opposite outer faces of the evaporator structure are formed and finished to conform closely to the desired parallel planes.

Iclailn:

1. In a vacuum type cold plate, an outer housing including parallel flexible sheet metal side wallssealed together about their edges in gas tight relationship, the interior of said housing being partly exhausted, an evaporator structure in the space surrounded by said walls, including headers and evaporator tubes extending between said headers, and inlet and outlet ducts for said headers, the outer surfaces of said sheet metal side walls lying in parallel planes, said headers and tubes having fiat surfaces opposed to the inner faces of said side walls, the number and spacing of evaporator tubes in the partly exhausted interior of the housing being sufficient to maintain the exterior surfaces of the side walls in substantially parallel planes, said tubes being rectangular in transverse cross-section.

2.'The structure of claim 1 characterized by and including an outlet header, the cross sectional area of which exceeds the cross sectional area of the individual tubes.

3. In a, vacuum type cold plate, an evaporator structure including a pair of parallel header tubes, an inlet duct connected to one of said header tubes, an outlet duct connected to and extending from the other header tube, a plurality of parallel rectangular evaporator ducts extending between and communicating with said header tubes, and spaced apart along said header tubes, an outer housing including two parallel, flexible sheet metal walls sealed together in as-tight relationship, the interior of said housing being partly exhausted, said evaporator-structure, including the header tubes and the evaporator ducts, havconforming generally to and surrounding saidheader tubes.

5. In a vacuum type cold plate, an outer housing including two parallel, flexible sheet metal walls sealed together in gas-tight relationship, said sheet metal walls having intermediate portions having plane outer surfaces parallel with each other, and having, along opposite edges, outwardly ofiset portions, and an evaporator assembly within said plate, said assembly being a reenforcement for said walls, and including headers extending along and within said offset portions, and rectangular ducts extending between the parallel portions of said walls, and connecting said headers.

HERMAN W. KLEIST.

REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS 35 Number Name Date 0,166,101 Kleist July 18, 1939 705,015 Barrett"... July 22, 1902 500,088 Wanner June 20, 1893 

